The present invention relates generally to a system for classifying a series of coins, tokens and the like, according to their denomination and more specifically to making such a classification determination according to the size of the coin.
Coin accepting devices are rather commonplace and include, for example, coin changers, laundromat equipment, vending machines, and the turnstiles or fareboxes associated with public transportation systems. Frequently the coin accepting device is mechanically configured to accept only certain denomination sizes, while other coin accepting devices may accept several different coins, and classify each coin according to a physical property of that coin. The weight of a coin may, for example, be used to determine its denomination, while some more sophisticated systems measure magnetic properties of the coin with still other systems making an optical determination of the coin size. This last category may be termed "optical coin identification".
The typical optical coin identifying system requires that the coin to be identified be precisely positioned as, for example, being against a fixed side wall or rail, and further requires that the coin be at a precise position along that engaged rail, whereupon its denomination is determined by a light sensing array and more specifically by the particular light sensors which are blocked by the coin, and the other particular light sensors which are not blocked by the coin. Such a sensing array is disclosed in U.S. Pat. No. 3,939,954.
Another optical coin identification system not requiring the coin being identified to be at a precise location is disclosed in the John A. Meyer copending patent application Ser. No. 900,497 assigned to the assignee of the present invention. This application is entitled "Token Identifying System" and the entire disclosure thereof is specifically incorporated herein by reference. In this copending application, an image of a passing coin chord is projected onto a linear array of light sensing elements and that linear array is repetitively scanned or interrogated to determine the maximum projected chord, with this maximum chord being interpreted as the coin diameter. The maximum coin chord identifying scheme of this copending application works well and functions independently of precise positioning of the coin as by a wall or rail, however, this maximum chord system is relatively complex and expensive to manufacture and maintain.